Just as an info: after fixing the #mimeDecodeToBytes: issue with recent image 70934 and later it is possible
to load Seaside again from GitHub using

Metacello new
 baseline:'Seaside3';
 repository: 'github://SeasideSt/Seaside:master/repository';
 load

into a recent Pharo 7.0 (load instruction as recommended on https://github.com/SeasideSt/Seaside).

For the deprecated warnings you either "Proceed" or disable them for the time being.

799 of 806 Seaside tests passes

470 of 457 Grease tests passes

primarily failing to to non-compatible streams. Seaside and Grease tests seem to test

some ANSI related things - who fail now.